fix: Ask renovate to add sign-off lines

See: https://docs.renovatebot.com/presets-default/#gitsignoff


Signed-off-by: Wiktor Kwapisiewicz <wiktor@metacode.biz>

renovate.json

 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
-    "config:base"
+    "config:base",
+    ":gitSignOff"
   ],
   "separateMinorPatch": true,
   "patch": {